This invention relates to a machine for shelling nuts and in particular to a multi-shaft mechanism for entrapping individual nuts for pressure cracking or shear splitting, depending on the type of nut to be shelled.
Prior art nut shelling devices utilize impact means or pressure rollers for crushing nuts. In general such devices shatter the nuts creating many small pieces of shell that must be separated from the meat, much of which may be broken. Since a premium is generally placed on shelled, whole nuts, these techniques not only create problems in separating meat from shell, but diminish the value of the product.
Certain nuts such as the macadamia nut have extremely tough shells with kernels that demand a substantial premium when whole. The nuts are relatively round in configuration and are often graded according to size before being shelled by crushing between two precisely spaced counter-rotating drums. Because of the force required to crack the nuts, often the kernels are broken as the thick brittle shell shatters. Frequently, the kernel or a substantial portion of the kernel remains lodged in the shell requiring further cracking to recover the meat or resulting in losses, if the retained meat is discarded with the shell. Other nuts such as walnuts have an oblong configuration with shells that are brittle and of varying thickness at different parts of the shell resulting in mixed results when cracked by impact or roller devices.
It has been discovered that various nuts lend themselves to different techniques for improved shelling, if the nut can be properly positioned and contacted by select shelling implements adapted to the particular nut. It has been known, for example, that upon positioning a walnut on end and impacting the opposite end, the shell will split generally leaving an unbroken kernel. However, design of a continuous process that will shell commercial quantities of nut using an individual nut positioning technique has eluded designers.
It is therefore a principal object of this invention to provide a nut shelling machine that entraps and orients individual nuts for action by select contact implements, and which can accomplish this task on a commercial scale with relatively simple components.
In one of the preferred embodiments this machine is provided with contact implements that splits and separates shells from the kernel and is particularly designed for shelling the tough macadamia nut and other round thick shell nuts. In another embodiment the machine is provided with contact implements tbat engage and compress the ends of a nut with or without cutting blades, and is particularly designed for shelling the brittle walnut and other oblong nuts.